Abstract

Brownian motionexperiments have become a staple of the undergraduate advanced laboratory, yet quantification of these experiments is difficult, typically producing errors of 10%–15% or more. Here, we discuss the individual sources of error in the experiment: sampling error, uncertainty in the diffusion coefficient, tracking error, vibration, and microscope drift. We model each source of error using theoretical and computational methods and compare the model to our experimental data. Finally, we describe various ways to reduce each source of error to less than 1%, improving the quantification of Brownian motion.

The authors would like to thank Amy Wagaman for careful reading of the manuscript. This work was supported by a Howard Hughes Medical Investigator undergraduate fellowship (MAC), a SOMAS-URM grant (JGT), and Amherst College.